VMF · Edition 02.11
7
0,1
0,2
0,3
0,4
0,5
0,6
0,8
2
1
3
4
6
8 10
20
30 40
1
0,8 1
2
3
4
6
8 10
20
30 40
3
0,7
1
2
3
4
6
8 10
20
30
200
300
500
200
300
100
200
300
2
60
100
60
100
40
60
1
2
3
4
5
6
8
10
20
VM
F 1
10
∆
p [mbar]
V'
n
[m
3
/h]
VM
F 1
15
VM
F 1
20
VM
F 1
25
VM
F 2
25
VM
F 2
32
VM
F 2
50
VM
F 2
40
0,2
0,3
0,4
0,5
0,6
0,8
1
0,4
0,5
0,6
0,8
1
2
3
4
5
6
8
∆
p [inch WC]
30 40
60
100
200
10000
400
2000 3000
5000
600
1000
1
V' [SCFH]
Standard
T-product
Flow rate
(
V·
n
)
Inlet pressure p
e
∆
p
max.
Medium temperature
Flow rate
(
V·
b
)
Product
3 .1 Calculating the nominal size
= natural gas (
ρ
= 0.80 kg/m3)
= propane (
ρ
= 2.01 kg/m3)
= air (
ρ
= 1.29 kg/m3)
The characteristic curves are measured at
15°C (59°F) with a measurement set-up in ac-
cordance with the standards EN 13611/EN 161.
This involves measuring the pressure 5 x DN
upstream and downstream of the unit under
test. The pressure drop of the pipe is also
measured but is not compensated for.
A pressure loss of 10 mbar must not be ex-
ceeded.
Reading instructions:
Should operating cubic metres (
V·
b
)
have
been used in the flow rate diagram, instead
of standard cubic metres (
V·
n
)
, then the pres-
sure loss read must be multiplied by the
absolute inlet pressure in bar (1 + positive
pressure in bar).
Example:
inlet pressure p
e
(positive pressure) = 0.4 bar,
gas type: natural gas,
operating flow rate
V·
b
= 15 m
3
/h,
selected filter module: VMF 120
∆
p from diagram = 3.1 mbar,
∆
p = 3.1 mbar x (1 + 0.4) = 4.5 mbar.
The VMF 120 has been selected correctly.
3 Flow rate
∆
p
v
●
Natural gas
0.80 kg/m3
20.9 m3/h
400
10.0
mbar
mbar
0 °C
15.0 m3/h
[mbar]
[m/s]
VMF 110 | 9.2| 29
VMF 115 | 4.5| 18
VMF 120 | 1.3| 11
VMF 125 | 0.8| 7
VMF 225 | 0.4| 7
VMF 232 | 0.2| 4
VMF 240 | 0.1| 3
